The Tektronix SCD1000 is a transient digitizer based on a scan converter tube. It is similar to a SCD5000, but the SCD1000 has a vertical amplifier instead of direct access. Because of this, the SCD1000 has 100 mV full-scale sensitivity, 50 times more sensitive than the SCD5000. However, the SCD1000 has only 1 GHz vertical bandwidth instead of the SCD5000's 4.5 GHz.
Vertical amplifier (compare the 7104's)